1. Field of the Invention
The invention relates to an accumulating conveyor, in particular for use in the motor vehicle industry, for example for conveying body parts.
2. Description of the Related Art
Accumulating conveyors are known. They generally consist of a motor-driven bottom strand and top strand which are used to convey pallets which serve to receive workpieces, for example sheet-like parts from body manufacturing, and from or else to which components can be removed or can also be supplied, for example manually, or else also by a robot arm. The strands of accumulating conveyors of this type move in two planes which are arranged one above the other and are generally horizontal, and run endlessly via reversing stations arranged at a distance from one another.
The invention is based on the problem of inventively refining an accumulating conveyor of the required type in such a manner that even heavier pallets are easily driven in a slip-free manner in the region of the reversing stations using structurally simple means.
The problem on which the invention is based is solved by an accumulating conveyor, in particular for use in the motor vehicle industry, for example for conveying body parts on pallets, comprising a flexible tension element which is driven, for example continuously, by motor, for example a chain or a belt which is guided in the region of the reversing stations via gear elements arranged on one shaft each, for example one drive wheel in each case, wherein the tension element is coupled to the relevant pallet by a device which can be actuated by a frictional connection, wherein the relevant shaft of the reversing station is assigned one driver wheel on either side of the shaft, said driver wheel having numerous recesses which are in each case arranged at preferably uniform angular distances from one another over the circumference of said driver wheel and in which a centering pin which is loaded by a compression spring is in each case arranged in a longitudinally displaceable manner, wherein, during the driving of the pallets from the top strand to the bottom strand and from the bottom strand to the top strand of the flexible tension element, in each case at least one centering pin of each driver wheel of the relevant shaft automatically engage in a form-fitting manner in recesses arranged on the underside of the relevant pallet and, after the relevant reversing station has been passed, also automatically slide out of said recesses again.
In the case of the invention, in the region of the loading and unloading station, even heavy pallets are conveyed in a slip-free manner from the top strand to the bottom strand and from the bottom strand to the top strand in a form-fitting manner via the centering pins and the driver wheels provided here. The centering pins engage automatically in recesses provided therefor on the underside of the relevant pallet and, at the bottom strand or top strand, also automatically come free again from said recesses after the pallet has been conveyed through the relevant reversing station by the tension element—chain or belt—which is driven, for example, continuously. Therefore, even heavy and loaded pallets are conveyed in a secure and slip-free manner through the reversing stations.
A possible embodiment of an accumulating conveyor arrange the recesses for the centering pins radially with respect to the center point of rotation of the relevant shaft, and therefore to the center point of rotation of the associated driver wheel. The centering pins can thereby be arranged in such a manner that, for example, of each driver wheel at the associated reversing station, for example in each case a plurality of centering pins, in particular two centering pins, grasp the relevant pallet in each case in a form-fitting manner.
A possible embodiment of an accumulating conveyor may couple the centering pins to the coupling recesses of a pallet over an angle of rotation range of approximately 180 degrees.
In a possible embodiment the pallets may be still coupled in the region of their horizontal in the region of the top strand as far as the horizontal region in the bottom strand to the driver wheels by the centering pins in a radially resilient and form-fitting manner. As a result, a secure and form-fitting connection or coupling to the pallets to be conveyed is produced virtually over the entire region of a reversing station.
A possible embodiment of an accumulating conveyor may have a braking device arranged next to the relevant driver wheel, said braking device braking the speed of the relevant pallet to zero or to the creep speed. This means that each reversing station has two braking devices of this type, and therefore even pallets conveyed up rapidly can be braked in order to ensure reliable entry of the centering pins into the cutout on the underside of the relevant pallet. For this purpose, for example, said cutouts on the underside can be elongated in the conveying direction or provided with run-on slopes.
A possible embodiment of the accumulating conveyor may be configured in such a manner that the pallets are forcibly guided on both sides of the accumulating conveyor in rails by means of guide rollers. Said rails can be, for example, of U-shaped design.
In a preferred embodiment, each reversing station has a drive wheel, wherein the underside of each pallet has two spaced-apart, central pallet pinions which are subjected to optionally adjustable friction force by brake pins, wherein the frictional connection to the tension element, which is optionally driven continuously, is overcome when the pallet comes to a standstill or the drive speed thereof is decelerated by means of a stopping device or by means of the braking device in the region of the reversing station. The flexible tension element may proceed continuously when the pallets are piled up or braked.
According to the invention, the underside of each pallet has, on opposite sides, at least one braking roller interacting with each braking device arranged here. A tilt-free braking to a standstill or into the creep speed of the relevant pallet is thereby brought about.
A possible embodiment of the accumulating conveyor may have an asynchronous drive motor for driving the flexible tension element, the rotational speed of which is regulable.
An embodiment of the accumulating conveyer may comprise an asynchronous motor driving the flexible tension element only in one conveying direction.
A possible embodiment of the accumulating conveyor may be advantageously assigned at least one stopping device.
Said stopping device can be used to stop the pallets in the conveying region such that the following pallets can catch up. The activation of a stopping device of this type can be incorporated into an SPC. The conveyor may also be assigned more than one stopping conveyor. Stopping conveyors of this type may be in addition to the braking devices at the particular reversing station or the reversing stations.
The invention is illustrated—partially schematically—with reference to an exemplary embodiment in the drawing, in which: